The present invention is generally relating to a jump-proof manhole/handhole, particularly to a manhole/handhole utilizing elastic fixtures for screws to combine a cover and a frame base. Furthermore, it is considerable to install a heightening frame between a cover and a frame base so as to heighten the cover leveled with road surface.
As shown in FIG. 9, a conventional manhole/handhole 500 comprises a cover 510 and a frame base 520. The cover 510 has a plurality of pull holes 511 for removing the cover 510 from the frame base 520 and the frame base 520 has an opening 521 in order to provide an entrance for workmen or machines to go in and out. A block portion 523 is formed at rims of opening 521 of frame base 520 so as to support the frame base and a projecting outer ring 522 is formed above the block portion 523 for containing and leveled with the cover 510. However, the cover 510 is a flat plate and the structure thereof is not strong enough so that it happens easily that the cover 510 deforms or jumps out from the frame base 520 when the manhole/handhole is overlaid or run over by vehicles.
A known jump-proof manhole is disclosed in Republic Of China (Taiwan) Patent Publication No. 176,915 xe2x80x9cstability-typed manholexe2x80x9d, which utilizes a concave formed on the frame base and a flange formed on the cover. The flange is corresponding to the concave for keeping close matching with each other so as to prevent the cover from jumping. However, if the manhole is overlaid or run over by heavy vehicles, the flange closely matched by the concave will split or bend resulting in more seriously destroyed and completely getting-stick. On the other hand, because of too large contacting area between cover and frame base, the cover and the frame base will get stick mutually so as to be unable to open the cover under invasion of moisture from outer circumstance.
Another known jump-proof manhole or handhole is disclosed in Republic Of China (Taiwan) Patent Publication No. 158,284, which comprises a cover and a frame base. There is a projecting isolated wing downward extending at the bottom of outer edge of the cover, which is embed on the inner edge surface of the frame base. The outer edge surface of wing resists the inner edge surface thereof for preventing the cover from jumping or sinking. Furthermore, when the manhole/handhole cover is overlaid or run over by heavy vehicle, such as truck or container car, the projecting wing of cover will split or bend so that no more resistance between cover and frame base resulting in jumping or sinking of the cover.
For the conventional manhole/handhole mentioned above, not only the problems of jumping, deformation or getting-stick due to rust, etc but also another common problem happens about the manhole/handhole. While paving the road at first time, the manhole/handhole was leveled with the paved road. The road surface will become rough after lasting a long time or working with other public construction so that the road surface needs to be repaired or re-paved again. While re-paving the road to form a second layer road base, a recess will be formed at the manhole/handhole to cause a serious problem of public security. In fact, in order to enable the manhole/handhole be leveled with road surface, the frame base of manhole/handhole must be dismounted and assembled again on the second layer of road base, then closing the cover. Therefore, the conventional manhole/handhole is labor wasting and time wasting for the entire road-working process.
It is a first object of the present invention to provide a jump-proof manhole/handhole. with a cover and a frame base. A plurality of elastic fixtures are combined on first through holes of frame base for connecting screw bolts which pass through the fixing holes of cover and the first through holes of frame base so as to combine cover and frame base without jumping of the cover while being overlaid by vehicles.
It is a second object of the present invention to provide a manhole/handhole with a heightening base for installing between the cover and the frame base. The heightening base has second pass holes which are corresponding to the second through holes of frame base for passing screw bolts. By means of stacking the heightening base on the frame base, the manhole/handhole is leveled with road surface and then the cover is installed on the heightening base for labor saving and time saving in re-paving.
It is a third object of the present invention to provide a manhole/handhole. A support strip is formed on a lower surface of a cover. While the cover is installed on a frame base (or heightening base), the cover is supported by a block portion of the frame base (or heightening base). An upper projecting peripheral frame of the frame base (or heightening base) has an unexposed interval with the support strip of the cover for preventing the cover rusting and lodge in the frame base (or heightening base).
It is a fourth object of the present invention to provide a manhole/handhole without deformation. The lower surface of the cover forms support strips, support blocks, and reinforcing bars. The reinforcing bars extend from the support strips or the support blocks to the center of the cover. The more close to the center of the cover, the more thickness of the cover is increased to form a strengthening portion on the lower surface of cover, so as to enhance structure strength of the cover. The cover doesn""t have permanent deformation while being overlaid by vehicles.
The jump-proof manhole/handhole in accordance with the present invention comprises a cover and a frame base. A plurality of support blocks, support strips, and reinforcing bars are formed on the lower surface of cover so as to enhance the structure strength of the cover so that the cover is uneasy to deform. The cover has a plurality of fixing holes to combine the cover with the frame base. The frame base has an opening and a bottom base for fixing on a road base. An upper projecting peripheral frame and at least a block portion are formed around the opening of the frame base. The block portion of frame base has a plurality of first through holes and a plurality of second through holes. Each first through hole is combined with an elastic fixture. A plurality of screw bolts pass through the fixing holes of cover and the first through holes of frame base and are locked to the fixtures so as to combine the cover with the frame base. Moreover, when the manhole/handhole needs to be heightened due to road working, a heightening base is installed between cover and frame base. The heightening base has an opening. An upper projecting peripheral frame and at least a block portion are formed around the opening of the heightening base. The upper projecting peripheral frame of the heightening base is stacked on the upper projecting peripheral frame of frame base. The block portion of the heightening base has a plurality of first pass holes and a plurality of second pass holes. A plurality of screw bolts pass through the second pass holes of heightening base and the second through holes of frame base so as to combine heightening base with frame base. Then the cover is placed on the upper projecting peripheral frame of heightening base and each first pass hole of heightening base is combined with an elastic fixture in order to combine cover with heightening base and seal the opening of heightening base.